Bacteria-a Primer Flashcards

1
Q

Major component of typical bacterial cell wall

A
  • diassacharides corss stitched by short peptides-peptidoglycan
  • capsule (polysaccharide capsule or slime layer)
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2
Q

What is different about cell wall of gram positive bacteria

A

Stains purple

Thick and contains teichoic acids

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3
Q

What is different about a gram negative cell wall

A

Stains red

Thin and surrounded by outer membrane (LPS/endotoxin)

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4
Q

Functions of capsule

A

Traps nutrients, aids in attachments, immune system avoidance, biofilm formation

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5
Q

What are the two disaccharides of cell wall

A

NAG and NAM

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6
Q

How many layers in gram positive cell wall

A

2 layers

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7
Q

How many layers do the gram negative cells have

A

Three layers

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8
Q

What are the 2 layers of gram positive cells

A

Thick peptidoglycan layer

Inner cell membrane

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9
Q

What are the layers of the gram negative cells

A
  • outer membrane with LPS
  • thin peptidoglycan layer
  • inner cell membrane
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10
Q

What color do fram positive stain

A

Purple

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11
Q

What color do gram negative cells stain

A

Pink

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12
Q

Which type of cell has endotoxins

A

Gram negative

  • LPS
  • lipid A
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13
Q

What type of cells are vulnerable to lysozyme and penicillin attack

A

Gram positive cells

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14
Q

What type of cells are resistant to lysozyme and penicillin attack

A

Gram negative cells

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15
Q

What component of the cell wall is only present in the gram positive cells

A

Teichoic acid

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16
Q

What is part of the cell wall that is only in the gram negative

A

LPS (endotoxin)

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17
Q

Though the gram positive wall is thicker, the gram negative wall has an _________

A

Outer membrane (LPS)

18
Q

What is the component of LPS that is endotoxin

19
Q

What type of bacteria normally produces endotoxin

A

Gram negative cells

20
Q

What triggers the release of endotoxins

A

Released when immune system loses GNRs

21
Q

Effects of endotoxins on the body

A

Systemic inflammation, fever, possible fatal shock

Maybe paralysis and diarrhea

22
Q

How do exotoxins get released

A

By replicating microbes

23
Q

Difference between endotoxins and exotoxins

A

Endotoxins get realized upon cell death and exotoxins get released when the microbes replicate

24
Q

What type of cell has endotoxins

A

Gram negative

25
What type of cell has exotoxins
All cells
26
What is the major class of toxins to which enterotoxins belong
Exotoxins
27
What are the 3 mechanisms by which enterotoxins can cause diarrhea
-action-inhibit NaCl resporion, activate NaCl secretion, or kill intestinal epithelial cells
28
What does the presence of lactose fermentation on MacConkey's agar mean
Fermenters will turn purple - KEE - Klebsiella - E coli - Enterobacter
29
What happens when there is a non fermenter on a MacConkey's agar
Colorless
30
What is the number one lactose fermenter
E. coli
31
What does beta hemolysis mean
Complete RBC lysis | -clear/yellow
32
What are some bacteria that have beta hemolysis
Strep pyrogenes/group A strep (GAS)/ strep throat
33
What is the purpose of MacConkey's Agar
Select for gram negative rods
34
What differentiates staph from strep on a mannitol salt
Catalase
35
How do you differentiate sta. Aureus and coag neg staph
Coagulase
36
If catalase is negative, what kind of bacteria do we have
Strep
37
If catalase is positive what kind of bacteria do we have
Staph
38
Once we determine that we have staph, how do we determine if it S aureus or S epidermidis/S sprophyticus
Coagulate - neg for s. Epidermidis and S sprophyticus - pos for S aureus
39
What is the most common cause of UTIs in women
S. Saprophyticus
40
Staph aureus grows on mannitol salt agar and turns the agar yellow. Predict the catalase and coagulate test results
Catalase-POS | Coagulase-POS
41
Is enterotoxin an endotoxin or exotoxin
Exotoxin